USA As Represented by Secretary of the Navy

The United States of America

Arne W Fliflet

Steven H Gold

David Lewis, Iii

Ralph W Bruce

M Ashraf Imam

Lynn K Kurihara

Syed B Qadri

David A Kidwell

Manfred Kahn

Edward P Gorzkowski, Iii

Bhakta B Rath

Richard F Hubbard

Jeffrey H Bowles

David Lewis

Melissa K Hornstein

Geoffrey B Smith

This disclosure concerns a method of making silicon carbide involving adding agricultural husk material to a container, creating a vacuum or an inert atmosphere inside the container, applying conventional heating or microwave heating, heating rapidly, and reacting the material and forming silicon carbide (SiC).

Silicon carbide synthesis

A method of sintering by: placing a compacted metal powder inside a cylindrically-shaped susceptor and in an inert atmosphere or a vacuum, and applying microwave or millimeter-wave energy to the powder until the powder is sintered.

Sintering of metal and alloy powders by microwave/millimeter-wave heating

A long-range active thermal imaging system includes an electromagnetic radiation source in the range of from about 10 GHz to about 500 GHz; a beam controller for receiving and retransmitting the electromagnetic radiation in a desired direction toward and onto a surface of a target, thereby heating the target and producing an infrared radiation emission from the target surface; and an infrared imager, e.g. an infrared camera coupled to a processor and display, for receiving the target's infrared radiation emission and generating a thermal image of the target. The radiation source may be selected such that the radiation penetrates into the target to provide a thermal signature, e.g. from subsurface features or objects. The thermal signature exhibits rapid changes that can be monitored in real time. This may allow surface or subsurface details or objects to be detected that would not otherwise be apparent.

Long range active thermal imaging system and method

A method for joining similar materials to create multi-component assemblies so the joint materials share similar physical, chemical, and electrical characteristics with the base materials. The method includes aligning the materials, applying joining material, focusing a microwave beam on the joint area to initially heat the joint area to allow the joining material to soften and fill physical discontinuities while the surrounding surfaces remains cool, rapidly heating the joint area to the reactive area of the joining material, rapidly cooling the joint area and maintaining the joint area at a recrystallization temperature. The materials can be ceramics such as aluminum oxide.

Microwave assisted reactive brazing of ceramic materials

A method of forming a nanocrystalline metal, comprising the steps of: providing a reaction mixture comprising a metal precursor and an alcohol solvent; continuously flowing the reaction mixture through a reactor; applying microwave or millimeter-wave energy to the reaction mixture; wherein the microwave or millimeter-wave energy is localized to the vicinity of the reaction mixture; and heating the reaction mixture with the microwave or millimeter-wave energy so that the alcohol solvent reduces the metal precursor to a metal; wherein the heating occurs in the reactor.

Microwave assisted continuous synthesis of nanocrystalline powders and coatings using the polyol process

Process for removing microwave energy absorbing material disposed on a substrate without thermally and/or mechanically damaging the substrate and with reduced production of volatile matter comprising the steps of directing microwave energy at the coating of sufficient power to damage the coating and removing the damaged coating from the substrate.

Removing radar absorbing coatings

Nanostructured metallic powders and coatings are processed by suspending a metal precursor in a glycol solution containing the constituent metal salts and using a millimeter wave beam as the heating source. The mixture is then heated to reduce the metal precursor to a metal precipitate. The precipitated metal may then be isolated.

Processing of nanocrystalline metallic powders and coatings using the polyol process

A high power, highly efficient, phase-stable frequency-multiplying magnicon microwave amplifier is disclosed having efficiencies that exceed 60%. The magnicon amplifier has an output cavity that receives an electron beam that is deflection modulated by the drive, gain and penultimate cavities of the magnicon amplifier. The output cavity is dimensioned so as to operate in a TM.sub.m10 mode, where m is an even integer greater than two. The output cavity is selected to preferably have an operating frequency f.sub.o which is twice the cyclotron frequency f.sub.c of the output cavity.

Magnicon amplifier operated at the second harmonic of the cyclotron

A gyroklystron device includes an electron beam source, a plurality of bunching cavities and an output cavity. A first bunching cavity has an input coupling aperture for receiving an rf signal from an rf signal injecting source. Each of the bunching cavities has a first pair of substantially uniform-angle slots of a preselected angle, which are diametrically opposed, and extend axially, parallel to the direction of the electron beam and extend into drift regions on both sides of the cavities. The first pair of slots control the Q of a desired mode and higher order modes. A second and third pair of slots are diametrically opposed and extend axially, parallel to the direction of the first pair of slots, but are rotated 90 degrees circumferentially from the first pair of slots. These slots control the axial profile of any mode that leaks out beyond the desired mode and control the length of field interaction with the electron beam. The second and third pair of slots begin in the walls of drift regions just beyond the first pair of slots, and have a preselected angle at their beginning and the angle increases in size along an axial distance away from the cavities. An outer vacuum jacket lined with rf absorbing material is also included such that rf energy leaving through the slots will not return.

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Alexandria, VA, United States of America

Arne W Fliflet